Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Cash and Cash Equivalents (Detail)

v3.10.0.1
Summary of Significant Accounting Policies - Cash and Cash Equivalents (Detail) - USD ($)
$ in Thousands
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents $ 120,357 $ 101,736 $ 138,285 $ 99,565 $ 106,514 $ 112,183
Cash equivalents 55,100   7,100      
Domestic Bank Accounts            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents 79,600   83,100      
Foreign Bank Accounts            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents 40,800   55,200      
Investments in Joint Ventures            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents 11,600   16,700      
Domestic Joint Ventures            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents $ 11,200   $ 10,000